Backlights are used to illuminate liquid crystal displays (“LCDs”). LCDs with backlights are used in small displays for cell phones and personal digital assistants (“PDAs”) as well as in large displays for computer monitors and televisions. Often, the light source for the backlight includes one or more cold cathode fluorescent lamps (“CCFLs”). The light source for the backlight can also be an incandescent light bulb, an electroluminescent panel (“ELP”), or one or more hot cathode fluorescent lamps (“HCFLs”).
The display industry is enthusiastically pursuing the use of light emitting diodes (LEDs) as the light source in backlight display technology because CCFLs have many shortcomings: For instance, CCFLs do not easily ignite in cold temperatures, they require adequate idle time to ignite, and they require delicate handling. Moreover, LEDs generally have a higher ratio of light generated to power consumed than other backlight sources. Accordingly, displays with LED backlights can consume less power than other displays, which renders LED-based displays more sustainable. LED backlighting has traditionally been used in small, inexpensive LCD panels. However, LED backlighting is becoming more common in large displays such as those installed in computers and television sets. In large displays, multiple LEDs are required to provide adequate backlight for the LCD display.
As larger displays include LEDs, complexity of associated circuitry and LED configurations can substantially increase, rendering conventional monitoring techniques and architectures largely inadequate. Such inadequacy not only arises from increased signaling and processing required to monitor performance of larger installed LED configurations and related circuitry, but also from increased manufacturing difficulty and cost, as density of wiring required to operate and monitor operation of LEDs in a display increases. Accordingly, conventional approaches to monitoring performance of LEDs in complex display or illumination applications can be improved.